Photographic exposure-meter.



No. 784,988. PATENTED MAR. 14;, 1905.

O. W. BAKE. v

PHOTOGRAPHIC EXPOSURE METER.

APPLIUATION FILED MAY 16. 1904.

' WITNESSES; A I a JNZENTUR W Sjwm 3V W4 a 2km7 M- ATTORNEY.

UNITED STATES Patented March 14., mos.

PATENT OFFICE.

CHARLES WV. DAKE, OF GRAND'RAPIDS, MICHIGAN, ASSIGNOR OF ONE- HALF TO\VILLIAM DONKER, OF GRAND RAPIDS, MICHIGAN.

PHOTOGPAPHIC EXPOSURE-METER.

SPECIFICATION forming part of Letters Patent No. 784,988, dated March14, 1905.

Application filed May 16, 1904. Serial No. 208,269.

To all whom, it may concern:

Be it known that I, OHARLEs W. DAKE, a citizen of the United States,residing at Grand Rapids, in the county of Kent and State. of Michigan,have invented new and useful Improvements in PhotographicExposure-Meters, of which the following is a specification.

This invention relates to a new and useful time exposure-meter for thepurpose of determining the length of time a photographcamera ought to beexposed in order to obtain the most perfect picture of the object to bephotographed; and the invention consists generally of a closed chamber,preferably of tubular form provided with suitable openings or openingfor the admission of light into such chamber, a visual figure in thechamber, an eye-opening for viewing the said figure, and suitable meansfor regulating the quantity of light which enters the said chamber.

The objects of my invention are, first, to produce a photographic timeexposure-meter by means of which the operator can quickly determine thelength of time he should expose his camera in order to produce the bestresults; second, to furnish a suitable meter, which notwithstanding thestrength of the light will quickly and accurately determine and indicatethe proper time for the camera exposure. These objects I accomplish bymeans of the mechanism illustrated in the accompanying drawings, inwhich Figure 1 shows a side elevation of the meter constructed inaccordance with my invention, illustrating the light-opening partiallyclosed. Fig. 2 is a longitudinal sectional view taken vertically withreference to Fig. 1. Fig. 3 shows my preferred form of the device usedin adjusting the quantity of light which passes into the chamber, saidform shown in Fig. 8 being adapted to fit into the tubular part of thechamber and to form an end piece therefor. Fig. 4 is an end view lookinginto the sleeve or cap illustrated in Fig. 3.

Similar letters refer to similar part s throughout the several views.

I prefer to form the chamber with an extension and also to form thechamber in tubular form, although the form and shape of the chamber maybe varied and the extension may .or may not be used.

In the drawings, A shows the outside shell of the chamber provided withone or more openings. In the form illustrated in the drawings a singleopening is used, which is broader at one end and extends to an angle atthe other.

.This is my preferred form.

shaped form F, as shown, and by turning the sleeve B the opening E inthe shell A of the chamber may be closed or partially closed or may beturned, as required. It is by this means that I regulate the amount oflight passing into the shell A for the pifrposes hereinafter described.

O is the extension part of the device, which in Figs. 1 and 2 is showndrawn out. This extension part may, however, be dispensed with, inasmuchas the same is used only as a matter of convenience in packing.

D shows the eyepiece, the eyepiece being cup-shaped, as shown by H, andprovided with a small opening I.

K represents any suitable figure opposite the eyepiece, which in theexample of myinvention is placed in the cap B and is made in the shapeof a cross. Any other form, however, may be used.

In order to determine the length of time the camera should be exposed inany given strength of light, I provide graduating-marks, which in theexample of my invention shown in the drawings I have indicated byseconds and fractions of seconds up to sixty seconds, beginning withone-fiftieth of asecond, more fully shown in Fig. 1. Thesleeve havingthe wedge-shaped form F is so constructed that when it is turned thesize of the opening will be indicated by the graduating-mark that is,

it indicates that the exposure of the camera should be one second. Inorder to determine the time of exposure the eye of the operator isplaced at D, so as to bring the figure K in range with the eye. The capor sleeve B is then turned, admitting light into the chamber until thefigure K appears to the observer. The index will then show the length oftime for the exposure. If the day is dark or the place is dark where thepicture is to be taken, the opening E must be enlarged, sometimes evento the extent of one minute. The time, however, will vary according tothe strength of light, and I have found by practical tests that whenfigure K appears to the eye, so as to be shown fairly in outline, theindex will accurately measure the time for the camera exposure.

In the drawings 1 have shown the graduating index placed upon the shellA; but the same may be placed in any suitable position, and I do notwish to limit myselfcither to the location of the index figures orcharacters nor to the number of such characters used. Neither do 1 wishto limit myself to the particular form of chamber, and it will beevident that the form may be changed, as well as the shape of theopening which admits the light into the chamber, and that other suitableways for admitting the light and regulating the amount of light receivedinto the chamber may be used.

Having thus described my invention, what I claim to have invented, anddesire to secure by Letters Patent of the United States, is-- 1. As anew article of manufacture, a pho tographic exposure-meter involving acasing forming a chamber and provided with a graduated light-inlet, saidcasing further provided with an eye-opening, and a sleeve arranged inoperative relation with respect to said casing having one end closed andfurther provided with anirregular-shaped inner end, said irregularshaped inner end of said sleeve adapted to gradually close saidlight-inlet, said sleeve having the inner face of its closed .endprovided with a visual figure.

2. As a new article of manufacture, a photographic exposure-meterinvolving aclosable chamber provided with a light-inlet, a visual figurewithin said chamber, a rotatable sleeve extending into said chamber forregulating the quantity of light admitted through said inlet, and anindex for indicating the time an object should be exposed for thepurpose of photographing.

8. As a new article of manufacture, a photographic ex posure-meterinvolving a closable chamber provided with an irregular-shapedlight-inlet, a visual figure within said chamber, a rotatable sleeveextending within said chamber and adapted to regulate the amount oflight admitted to said chamber through said inlet, said sleeve having anirregularshaped inner end, and an index for indicating the time anobject should be exposed for the purpose of photographing.

A. As a new article of manufacture, a pho tographic exposure-meterinvolving a casing forming a chamber and provided with a graduatedlight-inlet, said casing further provided with an eye-opening, and arotatable sleeve having one end closed and projecting in said casing forclosing one end thereof and further provided with an irregular-shapedinner end, said irregular-shaped inner end adapted to close saidlight-inlet in agraduating manner, said sleeve having the inner face ofits closed end provided with a visual figure.

5. As a new article of manufacture, a photographic exposure-meter,involving a closed chamber having an eye-opening and a grad uatedlight-inlet, and a rotatable means extending in said chamber forregulating the quantity of light admitted through said inlet andprovided with a visual figure adapted to be seen through saideye-opening.

6. As a new article of manufacture, a photographic exposure-meter,involving a closed chamber having an eye-opening and a graduatedlight-inlet, a rotatable means extending in said chamber for regulatingthe quantity of light admitted through said inlet and provided with avisual figure adapted to be seen through said eye-opening, and atime-register for indexing the time that a camera should be exposed,said index arranged in operative relation with respect to saidlight-inlet.

7. As a new article of manufacture, a photographic exposure-meterinvolving a casing forming a chamber and provided with a grad uatedlight-inlet, said casing further provided with an eye-opening, a sleevearranged in operative relation with respect to said casing having oneend closed and further provided with an irregular-shaped inner end, saidirregular-shaped inner end of said sleeve adapted to gradually closesaid light-inlet, and a visual figure arranged in operative relationwith respect to said casing.

8. A photographic exposure-meter involving a hollow tubular casing openat one end and having its other end provided with an extension having aneye-opening, said casing forming a chamber and said casing provided witha graduated inlet for admitting light into the chamber, a rotatableregulating means extending in said chamber and adapted when operated togradually close said inlet, thereby regulating the quantity of lightadmitted into said chamber, and a visual figure arranged in the chamberopposite said eye-opening.

9. A photographic exposure-meter involving a hollow tubular casing openat one end and having its other end provided with an extension having aneye-opening, said casing forming a chamber and said casing provided witha graduated inlet for admitting light into the chamber, a rotatableregulating means extending in said chamber and adapted when operated togradually close said inlet, thereby regulating the quantity of lightadmitted into said chamber, and a visual figure carried by saidregulating means and arranged opposite said eye-openin I 10. Aphotographic exposure-meter involving a casing forming a chamber, openat one end and having its other end provided with an extension having aneye-opening, a sleeve projecting in said chamber and having a closedouter end, thereby closing the open end of said casing, said sleevehaving an irregularshaped inner end, said inner end of said sleeveadapted when operated to gradually close said inlet, thereby regulatingthe quantity of light admitted into said chamber, and said sleevecarrying a visual figure arranged opposite said eye-opening.

11. A photographic exposure-meter involving a casing forming a chamber,open at one end and having its other end provided with an extensionhaving an eye-opening, a sleeve projecting in said chamber and having aclosed outer end, thereby closing the open end of said casing, saidsleeve having an irregular-shaped inner end, said inner end of saidsleeve adapted when operated to gradually close said inlet, therebyregulating the quantity of light admitted into said chamber, said sleevecarrying a visual figure arranged opposite said eyeopening, and atime-register for indexing the time the camera should be exposed, saidtimeregister arranged in operative relation with respect to said inlet.

12. As a new article of manufacture, a photographic exposure-meterinvolving an element having a graduated light-inlet, and an elementhaving an irregular-shaped end and arranged in operative relation withrespect to said first element, one of said elements rotatable within theother of said elements, causing thereby the gradual opening or closingof said inlet, thereby regulating the quantity of light admitted throughsaid inlet.

13. As a new article of manufacture, a photographic exposure-meterinvolving a closed chamber having an eye-opening and a graduatedlight-inlet, and a rotatable means for regulating the quantity of lightadmitted through said inlet and provided with a visual figure adapted tobe seen through said eye-opening.

14. As a new article of manufacture, a photographic exposure-meterinvolving an element having a graduated light-inlet, and an elementhaving an irregular-shaped end. for gradually closing said inlet,thereby regulating the quantity of light admitted, one of said elementssurrounding the other of said elements, and one of said elements beingrotatable.

15. As a new article of manufacture, a photographic exposure-meterinvolving an element having a graduated light-inlet, an element havingan irregular shaped end for gradually closing said inlet, therebyregulating the quantity of light admitted, one of said elementssurrounding the other of said elements, and one of said elements beingrotatable, said element provided with the inlet having an eye-openingand said element having the irregular-shaped inner end provided with afigure visible through said eye-opening of the other element.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

CHARLES W. DAKE.

Vv'itnessesz EDWARD TAGGART, MARY S. Tooxnn.

